1. Field of the Invention
The present invention relates generally to methods and apparatus for filling an endodontically prepared root canal, and more particularly, but not necessarily by way of limitation, to methods and apparatus for filling such a root canal with a thermoplastic material including gutta percha.
2. Description of the Prior Art
During endodontic procedures commonly referred to as root canal operations, one step of the procedure involves the filling of the root canal after it has been endodontically prepared, that is after it has been reamed out to remove pulpal tissue.
Endodontically prepared root canals are filled with a material commonly referred to as gutta percha. Gutta percha is commercially available in the form of gutta percha points which are elongated, tapered articles having a length of approximately twenty-eight mm and having a diameter of between approximately 0.15 to 1.4 mm. These gutta percha points may be held with tweezers or the like and inserted into the root canal. Once in place, they may be heated with a warmed instrument. A pick-shaped instrument commonly referred to as a condenser is then used to gradually push the softened gutta percha material down into the root canal to fill the root canal space.
There are many difficulties with this conventional use of gutta percha points. First, the points are difficult to handle, and a great deal of dexterity is required to place softened gutta percha points into the root canal opening and to compact that material so as to completely fill the root canal.
Several attempts have been made to improve upon methods and apparatus for placement of gutta percha material in an endodontically prepared root canal.
One approach is to use what is referred to as a gutta percha gun which is a device which heats a bulk quantity of gutta percha material and then forces the material through a hollow needle to place it in the root canal. One example of such a gutta percha gun is shown in U.S. Pat. No. 4,357,136 to Herskovitz et al.
Another approach has been to form the gutta percha material about an elongated shaft made of plastic or metal. The shaft with the material formed thereabout can be manually placed in the prepared root canal, and then the shaft is broken leaving a portion of the broken shaft along with the surrounding gutta percha material in place filling the root canal. Examples of such devices are shown in U.S. Pat. Nos. 4,758,156 and 4,894,011 both to Johnson.
Both of the devices described above have serious shortcomings.
The gutta percha guns like that of the Herskovitz et al. patent are very expensive and are bulky to use.
The devices like those of Johnson having a shaft imbedded in the gutta percha material are undesirable because they leave foreign material, namely the broken shaft, in the root canal. This foreign material can be very difficult to remove in the event that there is a failure of the root canal operation and it is desired to remove the filling materials.
Thus there is a need for a simple inexpensive means for placing gutta percha material in an endodontically prepared root canal. Further, there is a need for such means that provides a filling that does not include any foreign matter other than the gutta percha material.